Light bulb



FIG. 1 is a upper- front prospective view of the light bulb.

FIG. 2 is a front or rear view of the light bulb of FIG. 1, with the broken line showing for illustrative purposes only and forming no part of the claimed design;

FIG. 3 is a top view of the light bulb of FIG. 1.

FIG. 4 is a bottom view of the light bulb of FIG. 1; and,

FIG. 5 is a side view of the light bulb of FIG. 1. 

The ornamental design for a light bulb, as shown and described. 